>How about this...wouldn't using the "==" operator help speed things up i.e
>WHERE Table2.Id=="123"?

That's a good question. I don't know for sure, but I doubt it.

>And is there any difference in functionality and/or speed between the above statement and ...
>SELECT Table1.*
>FROM Table1, Table2 ;
>WHERE Table2.SeqNo=Table1.LinkField AND Table2.Id="123" ?

I don't think so, but again, I have not done extensive testing. Except in situations that need an outer join, I still use the "WHERE" sytax to join tables, just out of habit.